The major purpose of this core laboratory is to centralize important research techniques and procedures so as to improve overall economy and ensure better quality control. The core laboratory will make available a wide range of new techniques and reagents to program project investigators who may not have the time, resources, or expertise to develop these methods in their own laboratories. The core laboratory should make it easier for all investigators to take new approaches in their studies of cholesterol and bile acid metabolism in the liver and intestines. The core laboratory is divided into three sections: 1) cell culture 2) molecular biology and 3) "knock-out" mouse breeding and genotyping facility.